The Unmade Podcast (https://unmade.fm/) is probably my GOAT. Brady Haran (from Numberphile, Computerphile, etc.) and his Childhood friend, Tim Hein, come up with wacky ideas for podcasts that they won't actually make. Definitely the funniest podcast I've ever heard.

Hello Internet, also from Brady, with CGP Grey, is also amazing. Though sadly on hiatus.